The present invention relates to a quick-release plug-in coupling device for the breakaway connection of hoses and other fluid carrying conduits, particularly flexible hoses for watering and irrigating equipment.
Coupling devices of this general type have been in existence for a substantial length of time and generally are formed to include a male member connectable to a first hose portion and capable of being plugged into a correspondingly shaped female member connected to a second hose portion, the connection or attachment between the male and female members being achieved by an actuating member provided internally with elastic means extending through suitable openings in the body of the female member and engaging in suitable slots in the body of the male member.
Also known are coupling devices wherein a valve is located inside the female member for stopping the flow of fluid, such valve being activated when the coupling device is released, i.e. when the male member is withdrawn from the female member, to prevent further fluid flow through and from the disconnected device. Coupling devices of this type currently are formed of a variety of plastic materials, depending upon the particular application involved.
One known coupling device is disclosed in U.S. Pat. No. 4,219,222 wherein an actuating member of a quick-release coupling device is in the form of an axially sliding ring nut inside which are integrally molded plastic members used to achieve engagement between the male and female members. This known device however has the disadvantage that a double operation is required to release the coupling, i.e. the male member must be pushed against the female member while the ring nut is moved in a release direction. Furthermore, this known device is not entirely reliable, since the elastic members can get stuck during actuation and, as a result, breakaway from the actuating member. Also, this known device does not include a fluid sealing valve.
Another known arrangement is disclosed in U.S. Pat. No. 4,429,906, wherein a female member is provided with locking pawls that are pressed by elastic pushing means formed integrally as a single piece of flexible material. A coupling connection is achieved by directly plugging a male member into the female member, while an axially sliding ring nut is provided exteriorly of the coupling for releasing the connection. In this arrangement the advantage of improved convenience of use is offset by the disadvantage of the need for an additional elastic member which is difficult to mold. Also, this known device has reduced reliability due to the required high degree of accuracy during assembly and also due to the free moving elastic member inside the coupling device.
U.S. Pat. No. 4,660,803 discloses a further type of quick-release coupling device wherein a ring nut provided for actuating release of the device is formed internally with a number of elastic fingers intended to ensure engagement of a male member with a female member, as well as a number of lugs designed to lock the female member. A fluid sealing valve is located within the body of the female member and is locked in place between an annular projection provided interiorly of the female member and a tang mounted on an end part of a fluid feeding hose. This arrangement however still is quite complex due to the requirements of molding of the internal configuration of the actuating ring nut. Also, the tang provided on the end part of the fluid feeding hose is an additional element requiring assembly and that will not ensure a satisfactory fluid seal unless it is fused in position, which operation would require an additional manufacturing operation.
European Patent Application No. 02 19 705 discloses a fluid sealing breakaway coupling device wherein plug-in and locking members are integrally molded as a single piece with the body of a female member. This arrangement however substantially complicates the construction of the entire female member which thus must be formed of high quality expensive plastic material, for example acetal resins. Also, this arrangement still requires an external ring nut for actuating of the coupling.
Additionally, all such known types of coupling devices generally speaking have the disadvantage of possibly becoming released unintentionally or accidentally. Thus, this type of coupling device frequently is dragged along the ground where it can meet with obstacles of various types, such as stones, roots, edges of pavement, floors and flower beds, etc. Contact of the actuating member with such obstacle can result in unintentional release of the coupling.
Furthermore, all of these types of known coupling devices must be provided with suitable retaining means for ensuring that the actuating ring nut is retained on the device to prevent it from slipping off when coupling is released, as well as from displacing axially when the coupling is plugged-in. Normally, these retaining means are directly molded or otherwise provided in the body of the ring nut itself and are formed by suitable teeth engaging into corresponding catch slots in the body of the female member (such as described in the above discussed U.S. Pat. No. 4,660,803). This clearly requires that the molding operation of both the ring nut and the female member be substantially complicated.